EVANSVILLE — Authorities who investigated a series of mysterious late-night booms reported in two southwestern Indiana counties say the noises have subsided without any clear evidence emerging that could explain what caused them.

Several Vanderburgh and Warrick County residents reported hearing loud booms and window-rattling vibrations on the nights of Jan. 7 and 8.

Local agencies investigated the reports, but the Evansville Courier & Press reports no concrete evidence was found about the source of the noises. The Evansville-Vanderburgh County Emergency Management Agency's deputy director, Adam Groupe, says officials have not heard any additional complaints about the sounds.

Many theories were put forth about what caused the sounds. Some residents say they were noises such as airport traffic that just seemed louder on the two nights the sounds were heard.